package last.code.n;

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int r = 1;
        for (int i = 1; i <= n; i++) {
            r *= i;
        }
        System.out.println(r);
    }
}
